Fault Symptom
On the network, IPTV services are deployed; PIM-SM is run; static RPs are configured; the IPTV services of users are normal.
Due to network adjustment, all the IPTV services of users are interrupted, and the users cannot watch programs of any channel.
Fault Analysis
1. Run the display pim routing-table command to check the (S, G) and (*, G) entries on the device. You can find that the device cannot generate any entry.
2. Run the display pim rp-info command to check the RPs serving multicast groups. You can find that there are two RPs. One RP is a static RP with the IP address being a public network address, and the other RP is a dynamic RP with the IP address being a private network address.
By default, the dynamic RP takes precedence over the static RP. It is confirmed that the network uses static RPs based on network planning. The devices on the network, however, prefer the invalid dynamic RP, causing the IPTV services to be interrupted.
3. Run the debugging pim rp command. You can find that the IP address of the device that advertises the dynamic RP is 113.132.128.13.
<HUAWEI> debugging pim rp
*4.567973591 XA-FZC-FZCJ-K-MA52G-1.MAN PIM/7/RP:(public net): PIM ver 2 C-RP receiving 113.132.128.13 -> 222.90.205.94 on GigabitEthernet1/0/0 (S01534)
*4.567973591 XA-FZC-FZCJ-K-MA52G-1.MAN PIM/7/RP:(public net): C-RP 192.168.1.2, pref count 1, Priority: 192, holdtime 150 (S01553)
*4.567973591 XA-FZC-FZCJ-K-MA52G-1.MAN PIM/7/RP:(public net): 224.0.0.0/4 (S01583)
*4.567973592 XA-FZC-FZCJ-K-MA52G-1.MAN PIM/7/RP:(public net): Admin Scope Zone: 0 (S01584)
*4.567973592 XA-FZC-FZCJ-K-MA52G-1.MAN PIM/7/RP:(public net): Received C-RP-Adv from 113.132.128.13, npfx: 1, priority: 192, holdtime: 150, RP address: 192.168.1.2 (S04682)
You can use one of the following solutions to restore the IPTV services:
· Delete the dynamic RP configuration.
The prerequisite of this solution is that the configurations of the network devices are correct. This solution can temporarily prevent the fault, and cannot thoroughly rectify the fault.
· Increase the priorities of the static RRs.
This solution needs to be carried out on all devices on the entire network, and the workload is extremely heavy. Therefore, the solution is not feasible.
· Configure an ACL on the BSR to filter out packets from the invalid dynamic RP.
On the current network, the solution of configuring an ACL on the BSR is adopted, because site engineers do not have the right to modify the configuration of other devices.
Procedure
1. Run the acl acl-number to enter the ACL view.
2. Run the rule rule-id permit ip source ip-address command to configure ACL rules to permit packets from a valid RP to pass through. ip-address specifies the address of the valid RP.
3. Run the pim command to enter the PIM view.
4. Run the crp-policy advanced-acl-number command to limit the range of valid RP addresses.
Summary
The priorities of the following types of RPs are as follows:
· Static RP configured with the static-rp rp-address [ basic-acl-number | acl-name acl-name ] preferredcommand: has the highest priority.
· Dynamic RP: has the second highest priority.
Common static RP configured with the static-rp rp-address [ basic-acl-number | acl-name acl-name ] command: has the lowest priority.
